The present device relates to a writing instrument wherein the writing tip of the writing member may be effectively sealed when the writing tip is held in its accomodated position in an accommodating portion of the pen. The present device can be applied to a writing instrument such as a fountain pen, a felt pen or a ball-point pen, but can be mostly advantageously used when it is applied to a writing instrument such as the felt pen.
Writing pens having an improved sealing effect when the writing tip of the writing member is held in an accommodated state have been the subject of several patent documents. A writing instrument which has its barrel formed at its leading end with an accommodating portion so that its writing tip may be accommodated in that accommodating portion when it is held in its accommodated state is disclosed in applications such as Japanese Patent Application No. 50-122932 (i.e., Japanese Patent Laid-Open No. 52-49123), Japanese Utility Model Application No. 55-11902 and Japanese Utility Model Application No. 55-64915. However, the devices described in all of these applications are constructed such that there are formed, in juxtaposition to each other, in the leading end portion of a barrel, a through hole, through which the writing member can move into and out of the barrel, and an accommodating portion for accommodating the writing member. As a result, the leading end portion of the writing member is inevitably thickened such that the shape of the leading end portion cannot be made sharp. Another drawback that the writing member has to be formed into a special shape such that the writing tip protrudes from an eccentric position of the writing member.